$9.$ True$/$False: The absorption factor $($AF$)$ is a dimensionless number that indicates the efficiency of gas removal from the phase by the solvent.

$10.$ True$/$False: The height of a transfer unit $($HTU$)$ does not impact the total height of an absorption column necessary for the desired separation.

$11.$ True$/$False: When selecting a solvent, its boiling point is more critical than its absorption capacity for the target gas in the process.

$12.$ True$/$False: Graphical methods for stage estimation rely on the direct relationship between the operating line and the equilibrium curve to determine the number of stages.